On the Control of Elemental Composition, Macro-, and Microstructure of Directionally Solidified Additive Products from Nickel-Based Alloy

Abstract

The present work establishes the influence of heat input and methods of heat removal at the wire-feed electron beam additive manufacturing (EBAM) process on the structure of an additive product made of a nickel-based alloy. The following printing approaches are considered: changes in heat input, 3D printing strategy, and heat removal conditions due to (1) heating of the substrate, (2) partial suppression of radiative heat dissipation, and (3) thermal insulation of the substrate. It is shown that epitaxial growth of dendrites occurs in each case. However, in the case of an increase in speed and a change in the 3D printing strategy, the directed dendritic growth is interrupted. Preheating of the substrate and subsequent maintenance of the temperature reached during the EBAM process, as well as partial suppression of the radiative component of heat removal, allow to obtain the most uniform directional structure.

The Influence of Yttrium Content and Ceramic Crucible Materials on Desulfurization during Vacuum Induction Melting of DD5 Superalloys

“…The XRD peak spectra of the specimens prepared by the Al2O3 crucible and the Y2O3 crucible are shown in Figure 3. In these peak spectra, the reinforcing phase γ′ was mainly composed of the Ni3Al phase, the carbides were primarily the MC (TaC, MoC, and WC) carbides [34,35], and the precipitated phases of Y consist of M5Y ((Al0.15Co0.1Cr0.04Ni0.71)5Y and Ni5Y). After the casting process in the VIM, the remaining metal in the ceramic crucible formed a condensed shell on the inner surface as it cooled down.…”